Hoist linkage



J. F. HEALY HOIST LINKAGE Jan. ll, 1955 2 Sheets-Sheet l Filed Dec. 22, 1952 E T n' www' J. F. HEALY HOIST LINKAGE Jan. l1, 1955 2 Sheets-Sheet 2 Filed Deo. 22, 1952 '31 pivotally connected between links United States Patent Oce 2,699,320 Patented Jan. 11, 1955 HOIST LINKAGE James F. Healy, Chicago, Ill. Application December 22, 1952, Serial No. 327,206 3 Claims. (Cl. 254-135) drawings, in which:

igure 1 is a more or of the hoist prior to the commencement of a hoisting operation;

1a is a cross-sectional view illustrating the pivotal and sliding mounting for the mast;

Flgure 2 is a top plan View of the structure of Figure Figure 3 is an elevational for use with a structure 1; and

Figure 4 shows a shown in Figure 3.

As shown on the drawings:

While the invention has been illustrated somewhat diagrammatically, it will be appreciated that in practice the hoist linkage may be carried on a suitable tractor, it will be further understood that the present invenless schematic elevational View view of a movable fulcrum similar to that shown in Figure modification of the movable fulcrum for other purposes.

As illustrated in invention may rest include a fulcrum A support structure be secured thereto, and the support structure may carry a yoke 10 pivotally supporting a bearing sleeve 11 by means of pins 12. '1 `he sleeve 11 Figure 1, the structure of the present on a suitable supporting surface 8 and member 9 secured to the surface 8.

portion 20 for supporting the boom 14, and carries a shaft 16 pivotally mounting the boom 15. For constraining the boom to pivot in the clockwise direction with the shank 17, the shank is provided with an nected to the lower end of the leg 25 at 29. and a link 26 and 28 by pins 32 and 33. 33 may carry a roller 35 for riding on the web of the shank 17, and the pin 32 mav carry on the vertical riding support structure 10. The support structure may also linkage according to the present invention as Well as a lifting device U surface 37`of the 3 p rovide a stop member 40 for preventing clockwise rotation of the mast beyond the vertical position.

50 and extends downwardly and around a pulley 52 carried by shown) position shown in Figure 1.

In Figure 3 is illustrated a movable fulcrum comprising a body portion 75 swivelly mounting a neck piece 76 motion impetus -shank 77. he shank Fligure 1 so as to be utilized in Figure 4 illustrates a further movable fulcrum 82 for swivelly mounting a neck such as 76 in F may h receiving the neck 76 of F It will be understood that modifications and variations may be ellected without departing from the scope of the novel concepts of the present invention.

l claim as my invention:

l. A hoist linkage comprising a support structure including a fulcrum, a boom mounted for pivotal movement in opposite directions relative to said fulcrum, a mast guided by said support structure for axial movement and disposed above one end of said boom, means for transmitting the weight of the mast to said one end of the boom, lifting cable means engaging the other end of said boom and the top of said mast, and take-up means below said mast for drawing in said cable means, the tension in said lifting cable means exerting a downward force on said mast and an upward force on said other end of said boom.

2. A hoist linkage comprising a support structure having a vertical surface, a fulcrum member carried by said support structure, a motion impetus shank having one end pivoted to said fulcrum member, a boom pivoted intermediate the ends thereof to a point on said shank intermediate the ends of said shank, said boom having one end adjacent said vertical surface and the other end away from said vertical surface, means engaging said shank and said boom to cause said shank and boom to rotate together as the shank'pivots in the direction about said fulcrum member to raise said other end of said boom, a sleeve pivotally mounted by said support structure above said motion impetus shank, a generally upright mast having a straight portion slidably carried by said sleeve and having an angled oset foot portion extending downwardly from the lower end of said straight portion and angularly away from said vertical surface, a pair of links connected at one end to spaced points on said foot member and extending angularly toward said vertical surface, and a further link pivotally connected to the opposite ends of said rst mentioned pair of links to dene a quadrilateral linkage, said linkage having means at the lower corner thereof engaging said motion impetus shank and having means at the lateral corner thereof adjacent said vertical surface engaging said surface, pulley means carried by said fulcrum, pulley means carried at the top of said mast, and pulley means carried at said other end of said boom, and cable means anchored at said one end of said boom extending downward and around the pulley means carried by said fulcrum, upwardly around the pulley means carried by said mast, downwardly around the pulley means carried at said other end of said boom, and a take-up drum carried by said boom at said one end thereof receiving said cable from the pulley means at said other end of said boom, and means for driving said take-up drum to raise said other end of said boom.

3. A hoist linkage comprising a support including a fulcrum, a boom mounted for pivotal movement relative to said fulcrum in opposite directions, a generally upright mast, a pivotal mounting for said mast carried Ey said support and disposed above one end of said oom, ing an angularly offset foot depending below said mast, means for transmitting the weight of the mast to said one end of the boom through said linkage, means constraining said linkage to extend in the vertical direction upon pivotal movement of said mast in one direction about said mounting, cable means including a portion extending over the top of said mast and downwardly to the other end of the boom, and take-up means for taking up said cable to exert an upward force on said other end of said boom and a downward force on the top of said mast, whereby the mast tends to rock in said one direction to extend said linkage in the vertical direction to urge said one end of the boom downwardly and said other end of the boom upwardly.

Stewart et al. Oct. 14, 1884 Margot June 2, 1885 said mast having a quadrilateral linkage includ- 

